In recent years, the use of mobile devices such as smartphones and tablet computers has become widespread. Such mobile devices generally allow voice and data communications over wireless networks. Typically, these devices include additional features or applications, which provide a variety of functions designed to enhance user convenience.
Among such applications or features, a voice assistant application enables a mobile device to receive a voice command from a user for operating various functions or other applications in response to the voice command. For example, a voice assistant application may allow the user to speak a voice command to call a desired phone number, play an audio file, take a picture, search the Internet, or obtain weather information, without physically operating the mobile device by hand. Accordingly, the user may choose to use a voice command to control various operations of the mobile device in a variety of situations where the user may not wish to or cannot physically operate the mobile device.
Conventional voice assistant applications are often activated in response to a physical input by a user (e.g., by hand). However, since one of the purposes in using a voice assistant application may be to operate a mobile device without a physical input, the user may find it inconvenient or difficult to physically activate the voice assistant application. Thus, some mobile devices allow a user to activate the voice assistant application by speaking a voice command.
However, such mobile devices are often activated erroneously in response to various input sounds captured by the devices or fail to be activated in response to a proper voice command. For example, a mobile device may erroneously recognize another person's utterance as a proper voice command and activate a voice assistant application. On the other hand, when a mobile device is in a loud environment, the mobile device may not recognize a proper voice command due to the background noise and thus fail to activate the voice assistant application.